Field of the Invention
The present invention relates to a diagnosis device for a joint of sheet metal and a method of diagnosing a defect of a joint of sheet metal using the same, and more particularly, to a diagnosis device for a joint of sheet metal and a method of diagnosing a defect of a joint of sheet metal using the same that can diagnose the defect of the joint regardless of an ultrasonic wave irradiation condition by calculating and displaying amplitude ratios of reflection signals reflected from the joint at the time of irradiating an ultrasonic wave to the joint of sheet metal to be diagnosed.
Description of the Related Art
In general, as a means for securing stability of steel facilities or evaluating the quality of a product having a steel structure, inspecting whether a defect such as a crack occurs in a test member by ultrasonic detection is required.
An inspection method by the detection is generally divided into two methods, and universally, one method performs inspection while a person directly brings an ultrasonic sensor into contact with a test object and the other method is an automatic inspection method using a robot.
Meanwhile, when the ultrasonic sensor is brought into contact with the test object, an ultrasonic wave generated from an apparatus may be transferred to the inside of the test object only by closely contacting the sensor and the test object, but practically, it is substantially impossible to fully make the sensor come in close contact with the test object.
Due to such a technical problem, a detection method is used, which injects a medium made of a liquid between the sensor and the test object to transfer the ultrasonic wave generated from the sensor through the medium and in this case, the used medium may be diversified, but a so-call immersion testing method using water is in common use, which is suitable for automatic detection.
FIG. 1 which is accompanied illustrates a signal for evaluating integrity of a joint in an automatic examination method using a conventional immersion testing method and the immersion testing method measures an amplitude of a signal reflected from the joint to evaluate the integrity.
However, the immersion testing method is difficult to use when the test object cannot be dipped into water or has a complicated shape, and as a result, automatic examination is difficult.
Therefore, as illustrated in FIG. 2, Korean Utility Model Registration No. 20-0284334 discloses ‘a water circulation device of a jig for ultrasonic detection’ that enables detection by making water as a contact medium flow from a water tank 1 by using a pump 3 and thereafter, supplying the water onto the surface of a test object E through the bottom of a jig 2 and collect the water while maintaining airtightness.
However, the convention art has a complicated shape, and as a result, it is impossible for the conventional art to examine a test object which the ultrasonic wave is difficult to be irradiated.
Further, since contact force or a contact state of the jig 2 cannot be maintained under a predetermined condition, the sensor 5 is difficult to detect an accurate joining state of the test object E, and as a result, an ultrasonic detector 4 may inaccurately evaluate the integrity of the test object E.